Leeches are parasitic because they suck blood not giving any benifit but harm.
A constant factor could be the dose of the drugs and the species of the rats used.
<h3>What is a constant factor?</h3>
In an experiment, a constant factor is one that is not allowed to change al through the experiment. This one must be held as the same and not allowed to vary. A constant factor could be the dose of the drugs and the species of the rats used.
The factor that would be different for the experimental group and the control group the administration of the new drug.
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All the Puritan children were taught to read, to understand the Bible, and to know the laws of the country. Reading schools were usually the only education for girls, but boys would go to grammar schools after reading schools.